docs: document experimental switch-model command

Author: ebeckner-looptech

README.md

@@ -144,6 +144,27 @@ the agent calls these tools and reports back the resume command.
 > directory, so registering this server inside Cowork may not work even though registering
 > it in Claude Code does.
 
+## Experimental: switch the model without leaving Cowork
+
+`cowork2code switch-model` creates a **new Cowork session** that continues an existing
+conversation on a different model — so you can keep working in Cowork instead of moving to
+Claude Code.
+
+```console
+$ cowork2code switch-model --title "emerging" --to-model claude-sonnet-4-6
+New Cowork session: Research: emerging LLM trends (→ claude-sonnet-4-6)  (claude-haiku-4-5 -> claude-sonnet-4-6)
+Session id:  local_…
+Quit Cowork fully (Cmd+Q) and relaunch to see it on the new model.
+Cleanup: rm -rf "…/local_…" "…/local_….json"
+```
+
+This authors a session in Cowork's local storage (your own machine, your own data) and is
+**experimental and unsupported**: Cowork's on-disk format is undocumented and may change
+across updates. The original session is never modified, every run prints a one-line cleanup,
+and the new session's config and audit log are written with owner-only permissions.
+Rendering the conversation on the new model is reliable; whether the *next* turn retains full
+prior context depends on Cowork internals — verify before relying on it.
+
 ## What gets created in the target directory
 
 - The session's `outputs/` and `memory/` files.
@@ -184,13 +205,16 @@ Project layout:
 
 ```
 cowork2code/
-  paths.py        project-directory escaping and path resolution
-  transcript.py   locate, rewrite, and write transcript JSONL
-  discover.py     scan the sessions root and resolve selectors
-  notes.py        render the configuration-notes sidecar
-  rehome.py       plan and execute a re-home
-  cli.py          the cowork2code command
-  mcp_server.py   the local MCP server
+  paths.py          project-directory escaping and path resolution
+  transcript.py     locate, rewrite, and write transcript JSONL
+  discover.py       scan the sessions root and resolve selectors
+  notes.py          render the configuration-notes sidecar
+  rehome.py         plan and execute a re-home (Cowork -> Claude Code)
+  audit.py          build Cowork's audit.jsonl from a transcript
+  cowork_session.py synthesize a new Cowork session (switch-model)
+  _fs.py            shared file-tree copy helper
+  cli.py            the cowork2code command
+  mcp_server.py     the local MCP server
 cowork2code_mcp.py  zero-install uv launcher for the MCP server
 install.sh          install the CLI and register the MCP server
 ```